February 2016
Volume 57, Issue 2
Open Access
Letters to the Editor  |   February 2016
Transforming Growth Factor Beta Switch in Aqueous Humor of Patients With Fuchs' Endothelial Corneal Dystrophy
Author Affiliations & Notes
  • An-Katrien De Roo
    Translational Cell & Tissue Research Department of Imaging & Pathology, KU Leuven, Belgium; Department of Pathology, UZ Leuven, Belgium;
  • Sofie Struyf
    Lab of Molecular Immunology (Rega Institute), Department of Microbiology and Immunology, KU Leuven, Belgium; and the
  • Beatrijs Foets
    Department of Ophthalmology, UZ Leuven, Belgium.
  • Joost J. van den Oord
    Translational Cell & Tissue Research Department of Imaging & Pathology, KU Leuven, Belgium; Department of Pathology, UZ Leuven, Belgium;
Investigative Ophthalmology & Visual Science February 2016, Vol.57, 771-772. doi:10.1167/iovs.15-18768
  • Views
  • PDF
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      An-Katrien De Roo, Sofie Struyf, Beatrijs Foets, Joost J. van den Oord; Transforming Growth Factor Beta Switch in Aqueous Humor of Patients With Fuchs' Endothelial Corneal Dystrophy. Invest. Ophthalmol. Vis. Sci. 2016;57(2):771-772. doi: 10.1167/iovs.15-18768.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
We have read with great interest the article by Matthaei et al.1 on the expression of epithelial–mesenchymal transition (EMT)-related cytokines (monocyte chemoattractant protein [MCP]-1/chemokine [CC motif] ligand [CCL]2, transforming growth factor [TGF]-β1, TGF-β2, TGF-β3, basic fibroblast growth factor, tumor necrosis factor [TNF]-α, and interleukin [IL]-1β) in the aqueous humor (AH) of phakic and pseudophakic Fuchs' endothelial corneal dystrophy (FECD) eyes. With this letter, we want to confirm their findings on MCP-1, but contradict their findings on TGF-β2. Additionally, we present new data on inflammatory cytokines in the AH of FECD eyes. 
Matthaei et al.1 found a significantly elevated concentration of MCP-1, TGF-β1, and TGF-β2 in pseudophakic FECD eyes (FECDpsph) compared with cataract controls (which we will abbreviate as Controlph) and phakic FECD eyes (FECDph), but they observed no differences between FECDph and Controlph. They rightly concluded that there was no primary role for these aqueous cytokines in FECD pathogenesis, but that the upregulation of these EMT-associated proteins in FECDpsph was probably secondary to cataract surgery. 
Within the frame of a study into the molecular pathogenesis of FECD, we have recently conducted a similar experiment. Unlike Matthaei et al.,1 we also included a group with pseudophakic non-FECD edematous corneas (Edemapsph), and our analysis involved nine molecules in AH: five of them related to EMT (MCP-1, TGF-β1, TGF-β2, TGF-β3, and TNF-α), and four related to inflammation (IL-8/chemokine [CXC motif] ligand [CXCL]8, IL-6, growth-regulated oncogene α [GROα]/CXCL1 and IFN-α2). We compared Controlph (n = 21) with FECDph (n = 5), FECDpsph (n = 19), and Edemapsph (n = 8). The group Edemapsph consisted of both graft failures (n = 2) and pseudophakic bullous keratopathy (n = 6). Female/male ratio was 3:2 and all patients were older than 50 years. Magnetic bead ELISAs were purchased from Merck Millipore (Darmstadt, Germany). Plate readings were done with a suspension array system and software (Bio-Plex 200 System and Bio-Plex Manager, version 4.1.1.456; Bio-Rad Laboratories, Inc., Hercules, CA, USA). Undiluted AH was used in duplicate. 
Similar to Matthaei et al.,1 we observed a significant upregulation of MCP-1 in FECDpsph compared with FECDph (P < 0.05) and Controlph (P < 0.001; Fig.). In addition, we found MCP-1 to be significantly upregulated in Edemapsph compared with FECDph (P < 0.001) and Controlph (P < 0.001). Monocyte chemoattractant protein 1 did not differ significantly between both phakic groups and between both pseudophakic groups, respectively. This strengthens the conclusion of Matthaei et al.1 that MCP-1 does not play a primary role in the pathogenesis of FECD, but rather that it reflects a common response after cataract surgery. Like MCP-1, IL-8 was significantly upregulated in Edemapsph compared with both phakic groups: Controlph (P < 0.001) and FECDph (P < 0.01). Interleukin 8 was also significantly upregulated in FECDpsph compared with Controlph (P < 0.05). This suggests again that IL-8 does not play a primary role in the pathogenesis of FECD, but that the rise in IL-8 reflects a common response to cataract surgery. However, unlike Matthaei et al.,1 we did not observe an upregulation of TGF-β2 in FECDpsph compared with both phakic groups. Instead, we saw significantly less TGF-β2 in the AH of pseudophakic group “Edemapsph” compared with both phakic groups: Controlph (P < 0.05) and FECDph (P < 0.001). In addition, there was a significant difference in TGF-β2 concentration between both phakic groups (P < 0.05) and between both pseudophakic groups (P < 0.05), respectively, with a higher concentration in patients with FECD. This suggests that TGF-β2 is in fact specific for FECD within each category of phakic or pseudophakic eyes. 
Transforming growth factor β3 was below and TGF-β1 was above the detection limit in the study of Matthaei et al.1 In our study, it was the reverse. Therefore, we cannot comment on the findings for TGF-β1, but we can give new information on TGF-β3. There was significantly more TGF-β3 in FECDph compared with all other groups: Controlph (P < 0.01), FECDpsph (P < 0.01), and Edemapsph (P < 0.001). 
Both GROα and IL-6 were specifically and significantly upregulated in Edemapsph. Interleukin 6 was upregulated in Edemapsph compared with FECDph and FECDpsph (P < 0.05 for both comparisons). But there was no significant difference between Edemapsph and Controlph, nor between FECDph or FECDpsph and Controlph. Concentrations of GROα did not differ between FECDph or FECDpsph and Controlph either, but GROα was significantly upregulated in Edemapsph compared with all other groups (P < 0.001 for all comparisons). This suggests that the rise in GROα is specific for Edemapsph
These findings are in line with microarray expression analysis (MEA) and quantitative (q)PCR data that we have produced on FECDpsph corneal endothelium (CEn) compared with normal donor CEn (De Roo AK, Janssens T, Wouters J, Govaere O, Foets B, van den Oord JJ, unpublished observations, 2016). Quantitative PCR showed a significant upregulation of TGF-β2 and TGF-β3 and a significant downregulation of GROα in FECDpsph. Interleukin 6 and 8 were significantly downregulated in FECDpsph based on MEA, but not significantly changed on qPCR. Despite the increased concentration of MCP-1 in the AH of FECDpsph, the corresponding mRNA was significantly downregulated according to MEA, but not significantly changed according to qPCR. 
Our data on TGF-β2 and TGF-β3 combined with the data on TGF-β1 from Matthaei et al.,1 suggest that TGF-β2 and TGF-β3 are specific for FECD and that there is a switch toward TGF-β1 after cataract surgery. Notably, all three isoforms of TGF-β (1, 2, and 3) are expressed in the normal cornea, with TGF-β2 being present at the highest concentration and TGF-β3 at the lowest concentration.2 Interestingly, TGF-β2 is involved in tissue development2 and TGF-β3 is known to have an antiscarring effect (counteracting TGF-β1 signaling).3 On the other hand, TGF-β1 plays a role in wound healing and classical EMT, and has been proposed as a key player in the disease mechanism of pseudophakic bullous keratopathy.2 Furthermore, our data suggest MCP-1 and IL-8 to rise in response to cataract surgery. 
In conclusion, the TGF-β family of cytokines likely plays a role in FECD, but additional studies are required to define which members are involved in the pathogenesis, and which arise in response to surgery.1552 
Figure
 
Cytokine concentrations in aqueous humor. Transforming growth factors β2 and β3 are specifically and significantly upregulated in FECDph. Monocyte chemoattractant protein 1 and IL-8 are significantly upregulated after cataract surgery. Interleukin 6 and GROα are specifically and significantly upregulated in Edemapsph compared with FECDph and FECDpsph. Asterisks in individual graphs indicate the P value: *P < 0.05, **P < 0.01, ***P < 0.001. Error bars: display the mean and 95% confidence interval. Edema indicates non–FECD-related corneal edema and consists of both pseudophakic bullous keratopathy and graft failures. Graft failures (n = 2) are indicated in red. Distinction was made between phakic and pseudophakic eyes. Logarithmic (log) and square root (sqrt) transformations were used. The concentration itself was in pg/mL.
Figure
 
Cytokine concentrations in aqueous humor. Transforming growth factors β2 and β3 are specifically and significantly upregulated in FECDph. Monocyte chemoattractant protein 1 and IL-8 are significantly upregulated after cataract surgery. Interleukin 6 and GROα are specifically and significantly upregulated in Edemapsph compared with FECDph and FECDpsph. Asterisks in individual graphs indicate the P value: *P < 0.05, **P < 0.01, ***P < 0.001. Error bars: display the mean and 95% confidence interval. Edema indicates non–FECD-related corneal edema and consists of both pseudophakic bullous keratopathy and graft failures. Graft failures (n = 2) are indicated in red. Distinction was made between phakic and pseudophakic eyes. Logarithmic (log) and square root (sqrt) transformations were used. The concentration itself was in pg/mL.
Acknowledgments
The authors thank Nele Berghmans from the Rega Institute (KU Leuven, Belgium) for technical assistance. 
Supported by Perdaens Fonds Eye Research and the Fund for Research in Ophthalmology (FRO, Belgium). AKDR is a PhD fellow of the Research Foundation, Flanders (FWO). The authors alone are responsible for the content and writing of the paper. 
References
Matthaei M, Gillessen J, Muether PS, et al. Epithelial-mesenchymal transition (EMT)-related cytokines in the aqueous humor of phakic and pseudophakic Fuchs' dystrophy eyes. Invest Ophthalmol Vis Sci. 2015; 56: 2749–2754.
Reneker LW, Bloch A, Xie L, Overbeek PA, Ash JD. Induction of corneal myofibroblasts by lens-derived transforming growth factor beta1 (TGFbeta1): a transgenic mouse model. Brain Res Bull. 2010; 81: 287–296.
Tandon A, Tovey JC, Sharma A, Gupta R, Mohan RR. Role of transforming growth factor beta in corneal function, biology and pathology. Curr Mol Med. 2010; 10: 565–578.
Figure
 
Cytokine concentrations in aqueous humor. Transforming growth factors β2 and β3 are specifically and significantly upregulated in FECDph. Monocyte chemoattractant protein 1 and IL-8 are significantly upregulated after cataract surgery. Interleukin 6 and GROα are specifically and significantly upregulated in Edemapsph compared with FECDph and FECDpsph. Asterisks in individual graphs indicate the P value: *P < 0.05, **P < 0.01, ***P < 0.001. Error bars: display the mean and 95% confidence interval. Edema indicates non–FECD-related corneal edema and consists of both pseudophakic bullous keratopathy and graft failures. Graft failures (n = 2) are indicated in red. Distinction was made between phakic and pseudophakic eyes. Logarithmic (log) and square root (sqrt) transformations were used. The concentration itself was in pg/mL.
Figure
 
Cytokine concentrations in aqueous humor. Transforming growth factors β2 and β3 are specifically and significantly upregulated in FECDph. Monocyte chemoattractant protein 1 and IL-8 are significantly upregulated after cataract surgery. Interleukin 6 and GROα are specifically and significantly upregulated in Edemapsph compared with FECDph and FECDpsph. Asterisks in individual graphs indicate the P value: *P < 0.05, **P < 0.01, ***P < 0.001. Error bars: display the mean and 95% confidence interval. Edema indicates non–FECD-related corneal edema and consists of both pseudophakic bullous keratopathy and graft failures. Graft failures (n = 2) are indicated in red. Distinction was made between phakic and pseudophakic eyes. Logarithmic (log) and square root (sqrt) transformations were used. The concentration itself was in pg/mL.
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×